Issue 011, 2017SCIENCE FOCUS

Evolution of the Tuskless Elephant

The Story of Mankind

We Need Our Nails to Grow, So Stop Biting Them!

The Discovery of SCA40 with Prof. Ho-yin ChanSCA40 – The Rhinovirus with Dr. Ellen Foxman

Dear Readers,I hope everyone is getting some well-deserved vacation time this

summer after a year of studying and examinations. This issue of Science Focus has particular emphasis on the roots of humanity and the history and science of our ancestors. Find out how our species fare in space and read about the science behind unboiling eggs.

I would also like to use this platform to congratulate our newest Science Focus Article Submission Competition winner, Natalie Si Yeung Yu, of King George V School (Year 12), for her fascinating article on the science behind human finger nails. You can read her winning article on page 21. If you are interested in science and writing, send us your submission to our next Science Focus Article Competition for the potential to have your article published in our magazine and website, and an opportunity to win an Apple iPad Air. Visit our website for more details at http://sciencefocus.ust.hk.

Enjoy the rest of the summer and don’t forget to bring your copy of Science Focus to the beach!Yours faithfully, Prof. Yung Hou Wong Editor-in-Chief

Message from the Editor-in-Chief

Copyright © 2017 HKUST E-mail: sciencefocus@ust.hk Homepage: http://sciencefocus.ust.hk

Scientific AdvisorsProf Karen Chan Prof Tom CheungProf Daniel Lee Prof Pak Wo Leung Prof Ho Yi Mak

Editor-in-ChiefProf. Yung Hou WongManaging EditorJing Zhao

Student Editorial BoardEditors January Lok Yi Cheung Long Him Cheung David IuThomas LeeTwinkle Ching Poon David Ren

ReporterTeresa Ming Shan FanGraphic DesignersRinaldi Gotama Steve Min Kyu ParkTommy Wong

What’s Happening in Hong Kong? A Virtual and Augmented Experience 1

Augmented Reality, Creativity and the Arts

Save Orangutans at Hong Kong Ocean Park

Science in HistoryThe Immortalised HeLa 2

Science Today Double Act 4

Evolution of the Tuskless Elephant 6

MVP of Space Travel 8

Unboiling An Egg 10

Amusing World of Science The Story of Mankind 12

A New State of Matter: Time Crystals 16

Could Australia Be Drifting Away So Fast 18 That GPS’ Can’t Keep Up?

We Need Our Nails to Grow, So Stop Biting Them! 20

Who’s Who?The Discovery of SCA40 with Prof. Ho-yin Chan 22

The Rhinovirus with Dr. Ellen Foxman 24

Acknowledgements

ContentsScience Focus Issue 011, 2017

Zürich Meets Hong Kong – A Festival of Two CitiesThis October, you have the opportunity to partake in Zürich Meets Hong Kong, where the two world-class

cities join together to bring a week’s worth of events and activities to different venues in Hong Kong.

WHAT’S HAPPENING IN HONG KONG ?

1

A Virtual and Augmented Experience

You know those virtual reality headsets that are all the rage recently? Well, now you have a chance to experience the virtual reality of flying, animate your favourite cartoon characters, create art like a professional painter and more. Learn the science behind how virtual reality works and become part of the next generation of technology.

Location: Hong Kong Science Museum Date: Wed 25 October 2017Time: 7:00pm – 9:00pm

Augmented Reality, Creativity and the Arts

Onto more augmented reality! Technology and art combined creates something beautiful. Join Bryan Chung Wai Ching, Assistant Professor at Hong Kong Baptist University, and Robert Sumner, Associate Director of Disney Research Zürich to experience technology and art together.

Location: AAB201 Lecture Theatre, Hong Kong Baptist UniversityDate: Mon 23 October 2017Time: 5:00pm – 7:00pm

Save Orangutans at Hong Kong Ocean Park

Hong Kong Ocean Park and Zoo Zürich Switzerland will work together to save our beloved and endangered orangutans. But how does conservation work? In a guided tour, find out the “behind-the-scenes” of keeping endangered animals in modern zoos.

Location: Hong Kong Ocean ParkDate: Tue 24 October 2017Time: 10:00am – 12:00pm

7

arkand Zoo together to

References

[1] Scherer, W. F., Syverton, J. T., Gey, G. O. Studies on the Propagation In Vitro of Poliomyelitis Viruses. Journal of Experimental Medicine (1953). 97(5): 695-710.

[2] Brownlee, K. A. Statistics of the 1954 Polio Vaccine Trials. Journal of the American Statistical Association (1955). Volume 50, Issue 272.

[3] Harris, H., Miller, O. J., Klein, G., Worst, P., Tachibana, T. Suppression of Malignancy by Cell Fusion. Nature (1969). DOI: 10.1038/223363a0

[4] Schulman, A. N. What is the Body Worth? The New Atlantis (2012). Retrieved from http://www.thenewatlantis.com/publications/what-is-the-body-worth

[5] Jones, B. How Henrietta Lacks’ Cells Fueled Medical Breakthroughs. USA Today. Retrieved from https://usatoday30.usatoday.com/news/health/2010-03-09-

on the Propagation In Vitro of Poliomyelelitiit s Virusess.. Journanal ol of Experimental Medicine

ne Trials. Journal of the he Americri an Statistical Assocciaation (1955). Volume 50, Issue 272.

ana, T. Suppression of Malignancy by CelC l Fusion. Nature (1969). DOI:

eew Atlantis (2012). Retrieved from http://-the--bodbo y-worth

dical Breaeakthk roughs. USA Today. m/news/health/2010-03-09-

Immortality may be far from possible, but some cells have been passed on for decades. Scientists call them immortalised cell lines for the simple fact that they can be grown for extended periods of time in a standardised laboratory setting. For many years, a number of immortalised cell lines were harvested from different tissues and species, revolutionising bioscience research on the study of gene function, toxin and medication testing, and the development of vaccines and antibodies.

T h e f i r s t a n d m o s t w e l l - k n o w n h u m a n immortalised cell lines came from a cancer patient called Henrietta Lacks. While she was pregnant with her fifth child, Lacks complained of a “knot” sensation in her abdomen. After giving birth, Lacks suffered from a haemorrhage (or a ruptured blood

vessel). The bleeding was later diagnosed to be caused by a malignant cervical tumour. Lacks died in 1951, but unbeknownst to her, the cancerous tissue samples removed by her surgeon were sent to Dr. George O. Gey, a cell biologist at the Johns Hopkins Hospital. He noticed that the cancerous tissues were unique in that they were able to divide indefinitely in vitro from a single cell, something that he had never seen in the laboratory before. This became the first line of human cells to be isolated and immortalised, now known as the HeLa cell line [1].

Normal human cells undergo a process called cellular senescence, where repeated divisions cause the genetic materials to age and become unstable. In a laboratory setting, this happens typically after around 50 cell divisions in healthy

human cells. The mechanism is in place to prevent abnormal or faulty cells to self-destruct. However, cancer cells do not exper ience senescence and wil l continue to divide. In fact, HeLa cells are particular ly aggressive and care had to be taken to prevent them from contaminating other cells.

Requests for HeLa were made by other researchers not long after Dr. Gey’s publication, which gave rise to zillions of HeLa cel ls for scientif ic purposes. Since then, HeLa became a companion of researchers. Its impact on modern medicine is profound. For instance, the polio vaccine was tested on HeLa cells before going to human trial [1, 2]. Thereafter, HeLa became an instrument for studying the effects of viral infections for the invention of more vaccines. In the mid-1960s, HeLa was fused with mouse embryo cells to create the first

Since 1951, HeLa cells have made a significant impact in many areas of science and research.

Image credit: European Molecular Biology Laboratory (EMBL)/Jonathan Landry

cell hybrid, which helped researchers in mapping the human genome [3]. At present, HeLa has been widely used in virus and cancer research, medical diagnostics, and toxicology. It was also the first human cell line to be taken to outer space, where it divided just as fiercely as it did on Earth [4].

Sadly, Lacks never had the chance to give consent for her cel l s to be used for medical research. Furthermore, her family was not informed of further application until researchers tr ied to contact them to find out why HeLa cells were so aggressive in their replication, to the extent of contaminating other samples [5]. While the use of HeLa cells has raised numerous ethical concerns, it is undoubtable that i t s ex i s tence has saved millions of lives for decades.

yof further application until researchers tried to contact them to find out why HeLa cells were so aggressive in their replication, to the extentof contaminating other samples [5]. While the use of HeLa cells has raised numerous ethicalconcerns, it is undoubtablethat i t s ex i s tence has saved millions of lives for decades. HeLa

The Immortalised HeLa

By Thomas Lee

3

Mankind’s yearning to acquire knowledge of the vast unknown spaces of the universe has been a mission stretching back to antiquity. And when Earth inevitably succumbs to the test of time, it is to the great unknown we hold our hopes of survival. While we dream of grand interstellar voyages and the ultimate conquest of nature, understanding how our biology reacts to space travel is essential. Does the arduous task of space travel and zero gravity take a toll on our bodies?

In an attempt to further understand the effects of space travel on the human body, the National Aeronautics and Space Administration (NASA) initiated the Twins Study – a major research project encompassing ten separate researchers from diverse backgrounds, featuring multi-faceted collaboration between academia, government and industry.

Th i s unprecedented pro ject took Scot t Kelly, a NASA astronaut, on an orbital journey between April 2015 and March 2016, while his twin brother Mark Kelly stayed on Earth for a ground-based control subject. Identical twins share near ly 100% of thei r genome, making them close to perfect test subjects for genetic and epigenetic research. Whether the stressors caused by zero gravity or other external stimuli from space travel trigger epigenetic changes will be more apparent with an exact genetic copy to compare to. The researchers were thus able to document any unique biological changes between Scott and Mark as a response of being in space. In addition, the 340 day-long investigation incorporated exciting new techniques from an array of emerging fields. For instance, genetic sequencing was employed in the establishment of individual molecular profiles, contributing to the development of personalised medicine.

Preliminary results were released during the Human Research Programme Invest igators’

Workshop in January 2017 and revealed several int r igu ing phys io log ica l phenomena as a result of Scott’s stay at the International Space Station. Measurements before, during and after demonstrated notable divergences in DNA structure and gene expression patterns.

One st ructure that showed change was telomeres. Protective sequences of repetitive DNA situated at the ends of chromosomes, telomere shortening is a hallmark of aging and age-related diseases. While in space, the length of Scott’s telomeres increased, but eventually dropped back to his pre-flight levels after he returned to Earth. The implications of these results are still yet to be determined.

Meanwhile, changes in the gene-expression signatures were reported. Where such changes are associated with the ever-shifting environmental factors, like diet and sleep pattern, the changes i n Scot t seem ed m o re p ronounced tha n expected, prompting the question of whether there may be the activation of a “space gene”. It has, however, been hypothesised that gene exp res s ion could be affected by diet.

T h e challenge now i s t o u n t a n g l e how many of the observed changes are specif ic to the physical demands of spacef l ight — a n d h o w m a n y might be s imply due to natu ra l variations. And because the Ke l l y t w i n s a r e j u s t

NASA astronaut Scott Kelly

Double ActWorkshop in January 2017 and revealed severa

Double ActMankind’s i t

may be the activation pace gene”. It

owever, been hesised that expres s ion

be affected

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h o w m a n ybe s imply

o natu ra lons. And se thet w i n su s t

y

Witze, A. Astronaut twin study hints at stress of space travel. Nature (2017). Retrieved from http://www.nature.com/news/astronaut-twin-study-hints-at-stress-of-space-travel-1.21380

two people, the results may not be generalised to others. For the most part, the jury’s still out, and exactly how the stress of space travel leads to such changes remains to be delineated. As NASA eloquently put it, “Each investigation is like an instrument. On its own, it plays solo music. But put them all together and you have something incredible”.

Further results are expected to be published later this year, while integrated theme papers are due in 2018.

Identical twin brother Mark Kelly

Witze, A. Atravel. Natnature.costress-of-s

IdeMa

5

two people, the results may not be generalised

By David Iu

Elephants are often associated with their tusks. But these majestic biological structures are both a blessing and a curse. Highly sought for its ivory and poached to the point of endangerment, the number of African elephants born without tusks or born with smaller tusks has been increasing at an alarming rate, suggesting a selection disfavouring tusks.

The largest elephants typically bear the largest tusks, and in general, tusks grow as the elephant ages. Male African elephant tusks can grow up to seven times the weight of female elephant tusks [1]. Due to the fact that poachers tend to go after elephants with the largest tusks, male elephants are particularly targeted at their reproductive prime. Many of these elephants are therefore taken out of the population and can no longer pass on their genes related to the development of large tusks. Even if there are younger elephants that carry the genes for large tusks toward the line, either they are not ready to breed or their mating success is relatively low due to their smaller sizes. Poachers are artificially selecting for tuskless elephants, by eliminating large tusks from the gene pool.

Accelerated evolution of the tuskless elephant is not isolated in the African elephant alone. In fact, studies have documented that even female elephants with no tusks have increased from 10.5% to 38.2% between 1969 and 1989 – during the time when poaching was heaviest. In most elephant populations, a normal percentage of elephants born tuskless is anywhere between 3% to 4%, but by 1989, one National Park reported the tuskless

References

[1] Garrigan, K. Going Tuskless. African Wildlife Foundation. Retrieved from https://www.awf.org/blog/going-tuskless

[2] Morell, V. Recently Killed Elephants Are Fueling the Ivory Trade. Science (2016) Retrieved from http://www.sciencemag.org/news/2016/11/recently-killed-elephants-are-fueling-ivory-trade

elephant population to be between an alarming 9% and 25%.

The purpose of the elephant tusk is more far-reaching than an aesthetic feature. Tusks are specialised teeth that continue growing throughout an elephant’s life. If a tusk is broken off due to natural circumstances, the tusk will keep growing, unless the root of the tusk is exposed, which leaves the elephant to a very slow and painful death. Elephants use their tusks to fight, dig or move things. They also have the function of protecting the trunk of the elephant when they charge and defending an elephant from predators, which increases its survivabil ity. There is also the fact that female elephants prefer to mate with male elephants with tusks. Reduced mating could affect long term population size.

Despite the fact that the international ivory trade has been banned since 1989, illegal elephant poaching and ivory trafficking still run rampant in certain countr ies that lack the resources to battle poachers. Some surveys demonstrate that between 2007 and 2014, as many as 144 000 elephants were killed for their ivory [2]. Much of the demand of ivory stems from the nouveau-riche in Asian countries, who view owning items made of ivory as status symbols. Eliminating poaching entirely would require education and a collective global effort, but it is crucial to the survivability of elephants as a species and to prevent a tragic ending to these intel l igent, social creatures.

7

Evolution of the Tuskless Elephant

By January Lok Yi Cheung

This article may be useful as supplementary

reading for biology classes, based on the DSE syllabus.

By Rinaldi Gotama

Extinction – the end of a species of biological organisms. An estimated five billion species that have ever ex isted on Ear th are believed to be extinct. It happens for a variety of reasons, sometimes due to human interference, but also due to unforeseen natural circumstances. It can be marked by the death of the last organism of the species, but equally importantly is the quantity of the Minimum Viable Populat ion (or MVP), denoting the smallest size of a population required to avoid extinction for a certain period of time [1].

Extinction of a species is a common event that is currently estimated to occur at a rate of one species per year. One of the factors that lead to a species’ demise is stochastic perturbation, or random deviation of a system. These could be natural disasters for instance. An example of stochastic perturbation is in the extinction of the heath hen (Tympanuchus cupido cupido) [2].

Following a steady decline of the heath hen population during the early 1900s, conservation efforts rebounded the birds’ population to about 800 by 1916. In the summer of that year, a forest fire destroyed their nests and habitat, compounded by unusually high predation. These two random factors dramatically reduced the population to 100-150 birds. Then, in 1920, a disease outbreak caused the population to dip below 100. By 1932, the last heath hen was gone.

A species cannot hold off extinction once its population goes below its MVP. With a stable population around or above its designated MVP, a species is thought to be able to ward off stochastic per tubations. What about humans? By some counts, there were only 10 000 of us at one point in time [3], but being the resilient species that we are, we have now rebounded to around 7.5 billion and growing. With limited resources on Earth, the question is – what is the MVP we need for sustained space travel?

According to University of Florida’s Dr. John Moore, the number is 160 [4]. He obtained this number through a series of computer modelling he ran in 2002, setting the space travel period to 200 years and around 8 to 10 generations long. In fact, this model still held when extrapolated for 60 to 80 generations or approximately 2000 years. While that sounds low, history speaks otherwise. Clans of hunter gatherers, villages in pre-industrial societies and infantry groups in armies have been well-maintained by 150 to 180 people [5].

However, a more recent study by anthropologist Cameron Smith, reported a minimum of 10 000 people would be needed to weed out inbreeding and maintain genetic diversity. He mapped out the trajectories of five starting populations (150, 500, 2 000, 10 000 and 40 000) in their percent of genetic variation against the number of years, demonstrating that with a starting population of 150 people, inbreeding would cause a loss of over 80% of genetic diversity for a given hypothetical gene over 200 years. A starting population of 10 000 or more showed a high percent of variation, at close to 100% over at least 200 years.

“With 10 000”, Smith says, “you can set off with good amount of human genetic diversity, survive even a bad disease sweep, and arrive in numbers, perhaps, and diversity sufficient to make a good go a t H u m a n i t y 2.0.” [6]

50 to 180 people [5].

more recent study by anthropologist, reported a minimum of 10 000e needed to weed out inbreeding enetic diversity. He mapped out of five starting populations (150,

00 and 40 000) in their percent of

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References [1] Reed, D. H., O’Grady, J. J., Brook, B. W., Ballou, J. D., Frankham, R. Estimates of Minimum Viable Population Sizes for Vertebrates and

Factors Influencing Those Estimates. Elsevier (2003). Biological Conservation 23-24. Retrieved from http://www.wec.ufl.edu/academics/courses/wis4554/WebUpdate/ReadingsWIS5555/PVA/Reed%20et%20al%20PVA%20estimates%202003BiolCons113_23.pdf

[2] Shaffer, M. L. Minimum Population Sizes for Species Conservation. Bioscience (1981). Vol. 31 No. 2. Retrieved from http://www.co.monterey.ca.us/planning/major/Pebble%20Beach%20Company/Pebble_Beach_DEIR_Nov_2011/Pebble_Beach_DEIR_Admin_Records_Nov_2011/Shaffer/Shaffer_1981_Minimum.pdf

[3] Krulwich, R. How Human Beings Almost Vanished From Earth in 70 000 B.C. NPR (2012). Retrieved from http://www.npr.org/sections/krulwich/2012/10/22/163397584/how-human-beings-almost-vanished-from-earth-in-70-000-b-c

[4] Safety in Numbers. The Economist (2002). Retrieved from http://www.economist.com/node/998489

[5] Carrington, D. “Magic Number” for Space Pioneers Calculated. New Scientist (2002). Retrieved from https://www.newscientist.com/article/dn1936-magic-number-for-space-pioneers-calculated/

[6] Fecht, S. How Many People Does It Take to Colonise Another Star System? Popular Mechanics (2014). Retrieved from http://www.popularmechanics.com/space/deep-space/a10369/how-many-people-does-it-take-to-colonize-another-star-system-16654747/

Spac

e Trav

el

References [1] Reed, D. H., O’Grady, J. J., Brook, B. W., Ballou, J. D., Fran

Factors Influencing Those Estimates. Elsevier (2003).r Biolocourses/wis4554/WebUpdate/ReadingsWIS5555/PVA/Re

[2] Shaffer, M. L. Minimum Population Sizes for Species Conco.monterey.ca.us/planning/major/Pebble%20Beach%2Records_Nov_2011/Shaffer/Shaffer_1981_Minimum.pdf

Boiling an egg is a chemical change that uses heat to permanently alter the proteins in an egg in a process called denaturing. In this process, chemical bonds are broken and new ones are formed, causing chains of proteins to unfold and reset. Unlike physical changes, most chemical changes are difficult to reverse, but for the first time, international chemists have cracked the challenge of “unboiling an egg” – or really, folding protein.

Proteins are made up of long chains of amino acids and have a variety of essential functions within living organisms. DNA replication, molecule transportation and various metabolic reactions are all processes that rely on proteins. Folding proteins are important to many industries, from chemical reactions to medical research, but is a difficult process because proteins come out “tangled”. The same thing happens when an egg is boiled.

Gregory Weiss, a researcher at the University of California at Irvine and his team set out to untangle and fold the proteins of a boiled egg back into that of an unboiled egg. They separated the yolk from the egg white and boiled the latter for 20 minutes at 90 degrees Celsius to allow the proteins to become tangled clumps. The physical manifestation of the tangled proteins is the hard and solid appearance of the egg white. The chemists then added urea, the primary component of urine, to break down the proteins and rearrange them into liquid egg white form using a specialised machine known as the vortex fluid device. The device is key, as it uses the shear forces of stress to separate the entangled proteins and allow them to refold.

Weiss initially happened upon the vortex fluid device while visiting Australia’s Flinders University. The device was designed for intricate chemical reactions, where molecules are placed in a liquid to be spun in test tubes. The centripetal forces from spinning these test tubes are then applied to molecules in a controlled manner. Weiss realised that the same thing could be applied to tangled proteins when he saw that the device was able to separate molecularly-thin graphene from a block of graphite.

But while one of the main proteins that make up egg white – lysozyme – refolded nicely using this technique, different proteins have different shapes and not all behave the same way, calling for an investigation of the procedures required for each type of protein. Researchers discovered that a protein produced by E. coli for instance would not refold. To encourage folding, they locked down one end of the protein to a bead, similar to that of a weight, reproducing the natural way of folding for the protein.

Aside from being a fun science experiment, the effort has noble goals. To begin with, this discovery has the potential to minimise the cost of cancer treatment. Pharmaceutical companies typically create cancer-associated proteins by cultivating them inside costly hamster ovary cells, because this method prevents manufactured proteins from “misfolding” into undesired shapes during formation. Possessing a method to re-mold proteins from common E. coli bacteria or yeast could cut down costs of cancer research substantially by circumventing the need to cultivate proteins in the aforementioned method. In addition, the traditional path of salvaging protein is lengthy, whilst “unboiling an egg” only takes a few minutes.

Boiling an eggis a chemical change thatuses heat to permanently alter the proteins in an egg in a process calleddenaturing. In this process, chemical bonds are broken and new ones are

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Further ReadingLewin, S. Unboiled Egg Untangles a Knotty Protein Problem. Scientific American (2015). Retrieved from https://

www.scientificamerican.com/article/unboiled-egg-untangles-a-knotty-protein-problem/

Further ReadingLewin, S. Unboiled Egg Untang

www.scientificamerican.co

11

From a valley in Tanzania came a long-armed, hairy, ape-like creature whose genus would one day spread across the world. Homo habilis, or “Handy Man”, marks a bold step forward for the evolution of modern Homo sapien. Their brain capacity of 550cm3 to 687cm3 [1] was far larger than that of their predecessors. Improved cranial capacity lent credence to their name, especial ly s ince Homo habi l is are thought to have mastered s imple stone tools to butcher and skin animals [2]. Homo habilis continued to thrive in previously uninhabitable territory until they disappeared around 1.8 million years ago.

During the same time period, a new species named Homo erectus b e c a m e a n a to m i c a l l y d i s t i n c t to Homo habi l i s . Perhaps due to c h a n g i n g e nv i ro n m e nt s , H o m o erectus developed shorter arms that allowed for easier upright walking. Their larger skulls (800 cm3) and less robust skeleton suggested that Homo erectus depended on wit rather than brute strength. It was Homo erectus that f i rst made the journey out of Africa. In around one mill ion years, they spread into Europe, the Middle East and Asia.

The reason why ear ly man left Africa is still disputed. Some suggest the populat ion s i ze approached the woodland car r y ing capacity (maximum population size that an environment can support indefinitely). Exploration of the savannah offered opportunities for a few. These few would evolve over time to become better suited toward traversing the open ground and so would Homo erectus.

What is indisputable is how widely sp read the ape - men l ived: f rom Africa to eastern Asia, skeletal remains of Homo erectus exist. One famous example is the 750 000 year-old Peking Man, found near Beijing. The excavation site became a battlefield as the Japanese invaded, so it was decided that al l archaeological discover ies should be shipped away to New York for safety. No

one knows whether a vehicle ever came to haul away the discoveries, but if it did, no one knows where the vehicle went. However, the Peking Man was photographed meticulously, leaving behind a detailed description of late Homo erectus. He was far heavier in build than early Homo erectus, a sign of evolutionary adaption to colder climates.

Dating archaeological artifacts proves rather difficult. It was not until the discovery of carbon dating could archaeological f inds be dated accurately. The technique relies on a radioisotope of carbon – C14. Living matter contains a mixture of

This article may be useful as supplementary reading for chemistry classes, based on the DSE syllabus.

References

[1] Brown, G., Fairfax, S., Soarao, N. Human Evolution. Tree of Life (Web Project) (2006). Retrieved from http://tolweb.org/treehouses/?treehouse_id=3710

[2] Pobiner, B. The First Butchers. Sapiens (2016). Retrieved from http://www.sapiens.org/evolution/homo-sapiens-and-tool-making/

13

By David Ren

C12 (carbon’s most abundant and stable isotope) and C14, but C14 radioactively decays after the organism expires. A neutron in the carbon nucleus will convert into a proton after releasing a beta particle (electron) and an antineutrino, resulting in an N14 atom. By using a Geiger counter to measure the beta decay activity of an organic matter sample, it becomes possible to date the sample. To verify the validity of this method, peat trapped under glacier was carbon dated. Since it was known that the glacier formed during the last ice age, the accuracy of carbon dating was confirmed.

To understand whether Homo erectus could communicate in a recognisably modern way, carbon dating is not suff icient. An excavation on the island of Flores in Indonesia revealed an adult skeleton no more than 106 cm tall. Initially, the specimen was declared to be Sundathropus floresianus but the relatively large size of its skull compared with its height convinced researchers to classify it as Homo floresiensis. It seemed that Homo erectus had managed to reach Flores and lost height to become Homo floresiensis [3].

The island of Flores lies east of the Wallace line that marks the faunal ecospheres of South Asia and Australia. For most of history, the Wallace islands have been difficult to reach by land. For this reason, the evolutionary development of fauna only kilometres apart are vastly different [4]. The presence of humans east of the Wallace line 800 000 years ago suggests a great degree of cooperation and complex communication. Indeed, stone tools have been found on the island of Crete estimated to be 130 000 years old and on Flores since 800 000 years ago [5].

The loss of Flores Man’s height is a surprisingly common occurrence for large animals confined to small environments. Smaller hominids require l e s s fo o d, h a ve s h o r te r g es tat i o n p e r i o d s and have i m p roved thermoregulat ion in tropical climates. The dodo experienced the reverse phenomenon – gigantism. Upon first

arriving on Mauritius, the dodo was approximately the size of a pigeon. But after centuries without natural predators, the dodo grew larger; until it grew so large it lost its ability to fly [6].

Far away in sub-Saharan Africa, a distinctly mode r n ape - man was eme rg i ng. The new species, appearing approximately 150 000 years ago, displayed flatter faces, less muscular limbs and larger neural canals than Homo erectus or its predecessors. The developments reflected a preference for bipedalism and a greater capacity for communication. Two ice ages between 190 000 and 90 000 BCE pushed humanity to its limits. The dearth of fossil records during this period attest to the harshness of the environment. Some estimate that there were only 20 000 Homo sapiens alive in 100 000 BCE on the planet [7]. Adverse conditions encouraged genet ic mutat ions to f lou r i sh, particularly those favouring higher intelligence. When climate conditions settled, humans with those genetic mutations were able to out-compete other ape-men. As the human homelands struggled with an increase in population, people migrated out of Africa via the land bridge at Somalia into the Middle East.

Civilisation began soon after the end of the last Ice Age at around 13 000 BCE. Within the “lucky latitudes”, hunter-gatherers were able to begin to leverage a warmer planet. No place was better suited than the Hilly Flanks, incorporating the Tigris, Euphrates and Jordan Valleys in the Middle East. Desperate and hungry, people had deposited seeds into ferti le soil and stayed year-round to ensure they grew into healthy crops.

Humanit y sp read to ever y corner of the g lobe i n a re lat i ve l y sho r t pe r iod of t i me, overcoming multiple ice ages on the way. We have demonstrated our ability to adapt to new challenges like no other creature due to complex

communication, cooperation and intel l igence – and we continue to show this spirit as the challenges of the 21st century loom overhead.

ww

References[3] Brown, P., Sutikna, Morwood, M. J., Soejono, R. P., Jatmiko, E., Saptomo, W., Due, R. A. A New Small-Bodied Hominin From the Late

Pleistocene of Flores, Indonesia. Nature (2004). DOI: 10.1038/nature02999

[4] Smithsonian National Museum of Natural History. “Hobbits” on Flores, Indonesia (2016). Retrieved from http://humanorigins.si.edu/research/asian-research-projects/hobbits-flores-indonesia

[5] Bower, B. Hominids Went Out of Africa On Rafts. Wired (2010). Retrieved from https://www.wired.com/2010/01/ancient-seafarers/

[6] Tyson, P. Gigantism & Dwarfism On Islands. PBS (2008). Retrieved from http://www.pbs.org/wgbh/nova/evolution/gigantism-and-dwarfism-islands.html

[7] Morris, I. Why the West Rules – For Now: The Patterns of History and What They Reveal About the Future (2011). Retrieved from https://books.google.co.uk/books?id=bMi1XVXAl48C&pg=PA3&source=gbs_toc_r&cad=3#v=onepage&q&f=false

15

Crystals, microscopically arranged in a highly ordered fashion of molecules, are common solid structures of many compounds and elements. The crystal’s structure is distinguished by its unit cell, which consists of at least one atom within an imaginary cube, repeated and stacked in three-dimensional space in any direction. Snowflakes, for instance, are typically a single crystal or a conglomerate of several crystals. Solid sodium chloride, or more commonly known as table salt, is another example of a common crystal. Or perhaps most iconic is the giant covalent network of diamond. These tangible structures are easy to grasp, because they exist in space. Yet, in 2012, the same idea of a repeated structural unit in time was proposed by Nobel laureate Frank Wilczek, known as a time crystal.

These abstract structures would pulse without the need of energy input. Instead of a repeating unit of molecules that extend in all directions of a crystal lattice in space, a time crystal would theoretically consist

By Long Him Cheung

A New State of Matter:

References [1] Powell, D. Can Matter Cycle Through Shapes Eternally? Nature (2013). Retrieved from http://www.nature.com/news/can-matter-cycle-

through-shapes-eternally-1.13657

of a pattern that repeats in time, akin to “a clock that ticks forever without being wound”. [1] Furthermore, unlike a wave’s periodic oscillations, time crystal oscillations would be intrinsic, whereas wave patterns demand a driving force. Wilczek’s proposition to physically manifest this abstruse idea was met with several challenges.

Most fundamentally, the idea that a pulse could oscillate perpetually without initial energy input seems to defy the laws of thermodynamics. Symmetry in physics, for instance, means that the laws apply to all points in space and time, yet there are exceptions to the rules. At the ground state or its lowest energy level, a magnet will fall toward either north or south – that is they are asymmetrical since they look different on both sides. Crystals in space are also asymmetrical at their ground states, and do not look the same on all sides. However, regardless of symmetry, crystals in their ground states do not move unless given energy

because by definition, that is where something is at its most stable state. Objects with asymmetry across time instead of space would then be considered as time crystals. The notion is counterintuitive because it is analogous to an object in its ground state moving around without added energy. For example, if one were to drop a marble in a bowl, the marble should intuitively come to an eventual rest, but instead the marble continues to roll around perpetually.

However, scientists from the University of Maryland and Harvard reported to have independently created time crystals, except neither party’s time crystals fit the definition of what Wilczek initially proposed. Alternating lasers were fired at a chain of ytterbium ions so that the chains are constantly oscillating in random directions. What was significant was that even after the frequency of the initiations were changed, the oscillation did not change. Crystals in space are likewise stable to changes to their repeated structures.

There is still some debate as to whether this type of system is a time crystal as it fulfills time asymmetry but still requires some type of energy input to begin with. Scientists believe that the stability from these systems may have applications in quantum computing.

17

Time Crystals

Missing continent: houses 20 mill ion people, last seen 5 feet to the south. Notice any problem? Yes, the t it le is mis leading and the adjustment is actual ly quite smal l compared to Australia’s gigantic size of 8,600,000 square kilometres. Though, putting in perspective how points are projected on the Global Positioning System (GPS), how the continent moves does affect the accuracy of locating someone, or impair the ability to differentiate between two neighbouring places. As Australia continues on its journey to the north, the GPS would be due for a major adjustment once every couple of years – and the next one is scheduled at the end of this year.

The GPS is basically a giant map of our three-dimensional world. That is, we can know precisely where everyone, everything, every place is by simply obtaining three numbers – the x, y and z

numbers form the basis for a global positioning system; by treating the world as one giant grid of coordinates; one can assign numbers to each and every specific place, thus annotating their respective positions.

If you would like to know more about the physics of the GPS, please read Science Focus Issue 10 “The GPS and Its Connection to Relativity”.

Cartography, the study of maps and pinpointing locations, is a delicate art. Maps are but static projections of our dynamic, ever-changing world. Every once in a while, the sets of reference points used to locate places on the coordinate system have to be updated. These reference points constitute a geodetic system which approximates or defines geographical distances, i.e. the latitude, longitude and altitude relative to these reference points, and make up the vir tual framework on which we overlay the real world on. Usually, these reference points are major static structures such as roads and electrical grids, surveyed relative to other existing reference points. However, this implies that densely populated areas would be much better mapped than sparsely populated ones – in fact, Alaska is only as well mapped as Mars in this sense! [1]

Now, back to Australia. The current geodetic datum for the land down under was formalised way back in 1994. Updates for these datums have been sporadic – Australia has only ever seen three renditions of geodetic datums. Any further changes to the grid matrix of locations are based on the 1994 datum, minor edits and marks on a stationary canvas. The thing is, all continents are essentially

tectonic plates floating around, coll iding and sliding against each other – land masses shift over time, and Australia is no different. Except, Australia’s movement has exceeded that of other continents due to its unique geology. The last update for the geodetic datum, i.e. the 1994 one, corrected its latitude and longitude by a staggering 656 feet.

“Some countr ies are more stationary than others. When there is a significant shift in land masses over time we need to revise the models of the Ear th from which GPS coordinates are calculated, so for example your neighbour doesn't end up with your old coordinates,” said Damien Saunders, Director of Cartography for National Geographic.

Aside from the adjustment set for the end of this year, plans have been made for a modernised datum to be introduced by 2020, in order to keep up with the pace of advancements in mapping technologies – which is probably way faster than the rate at which Australia drifts. It’s not that Australia is drifting away so fast the GPS couldn’t keep up – we know where it is, we are just constantly pushing the very boundaries of precision and accuracy.

d Damien National

he end of odernised order to ments in ably way drifts. It’s t the GPS

we are just precision

19

References [1] Bourne, J. K., Jr. Alaska Has Finally Been Mapped as Precisely as Mars. National Geographic (2016). Retrieved from http://news.

nationalgeographic.com/2016/09/alaska-has-finally-been-mapped-as-precisely-as-mars/

By David Iu

You have mos t l i ke l y seen a f r iend whose nai ls are uneven and jagged stubs, or perhaps you have them yourself. Onychophagia is the compulsive act of biting one’s nails. It is surprisingly prevalent at young ages, around 45% of adolescents are nail-biters, and it may become a lifelong habit [1]. Onychophagia is also identified as an obsessive-compulsive disorder (OCD). For long-term nail biters, to rid of this compulsive behaviour, a 2012 study suggested that becoming aware of the need to rid the habit is one of the first steps [2]. So, to fellow nail biters, friends and families supporting our kind, let us understand why our nails are gifted to us and what biting them might incur.

Our nails have several important functions, including protecting the delicate phalangeal tissue and allowing for precise mechanical movements. Fingertips have high innervation density and are very sensitive. Our fingernails contribute to this feature by providing a counterforce to the fingertips when the finger’s skin is touched, which heightens two-point discrimination [3]. Nails also

enhance the precision of the pincer grip, the finest grip that humans can muster [4]. So how do these useful appendages grow and how can onychophagia stunt this?

The visible nail or the nail plate is composed of keratin, a fibrous protein which gives the nail its translucent nature. This plate is held down to the nail bed by the proximal nail fold (the skin around your nail) and the eponychium (the cuticle) [5]. The growth of the nail begins at the nail matrix which is part of the nail bed. The cells near the matrix replicate and undergo enlargement. The nail folds limit the

direction of growth and the duplicated cells grow distally toward the nail plate. The newly formed cells flatten and elongate from the resistance of the established nail [6]. Eventually, the nail plate is pushed out forming the free edge of the nail.

Nail-biting can cause irreversible damage to this growth process. By removing the free edge of the nail plate and exposing the distal nail bed to the environment, the nail bed can “irreversibly disappear” thereby permanently shortening the nail plate [7]. With less of a free edge, not only is a smaller area of the finger protected, but p rec i s ion manoeuv res a re impeded. Onychophagia can a l so i nc rease the r i s k of onychomycosis, a fungal i n fect ion of the na i l , which can stunt

n a i l g r o w t h

a n d contr ibute

t o t h e d es t r u ct i o n

of the nail bed o r t h e m a t r i x

[ 8 ] . W i t h s u c h delete r ious ef fects ,

c o m p o u n d e d b y t h e unhygienic factor, it is hardly

surprising that a social stigma exists for nail-biting.

For young children, when onychophagia has yet to develop beyond occasional biting, we can make use of biological responses and use topical bitter concoctions to discourage biting [2].

We Need Our Nails To Grow, So STOP Biting Them!

thereby permanently shortening the7]. With less of a free edge, not only area of the finger protected, ion manoeuv res a re

Onychophagia canase the r i s k of

cosis, a fungal of the na i l , tunt

n a i l g r o t h

21

Research suggests that incentive is a useful remedy, and can be particularly effective for older children. But when all else fails and no amount of instinctive responses or information gathering can strike the habit, stigmatisation may be the only way left.

Let m e e n d w i t h a co nfes s i o n a n d t h e unfortunate irony of the nail-nibbling that occurred when I wrote this article. I am beyond the age of relying on biological responses, and I have learnt (even written) about onychophagia. I guess I have no choice but to ready myself for the only other option now: come my way, social stigma!

References [1] Leung, A. K., & Robson, L. M. Nailbiting (1990). Clinical Pediatrics,

29(12), 690-692. doi:10.1177/000992289002901201

[2] Sachan, A., Chaturvedi, T. Onychophagia (Nail biting), Anxiety, and Malocclusion (2012). Indian Journal of Dental Research, 23(5), 680. doi:10.4103/0970-9290.107399

[3] Johnson, B. A., Wang, Q. C. Fingertip Injuries. American Family Physician (2001): n. pag. Web. 20 May 2017.

[4] Palastanga, N., Derek, F., and Soames, R. W. Anatomy and Human Movement Structure and Function (2013). Burlington: Elsevier Science. Print.

[5] Berker, D. A., De, R., Baran, R. Science of the Nail Apparatus (2012). Baran & Dawber's Diseases of the Nails and Their Management. doi: 10.1002/9781118286715.ch1

[6] Benjamin, P. Z., Scott, S. T., Reena, B. A. Nail Anatomy (2016). Retrieved from http://emedicine.medscape.com/article/1948841-overview#a3

[7] Lee, D. Y. Chronic Nail Biting and Irreversible Shortening of the Fingernails (2009). Journal of the European Academy of Dermatology and Venereology. doi: 10.1111/j.1468-3083.2008.02760.x

[8] Elewski, B. E. Onychomycosis: Pathogenesis, Diagnosis, and Management (1998). Clinical Microbiology Reviews 415–429. Print.

(even written) aboutno choice but to reoption now: come my

W inning article of the Science Focus Article Submission Competition.

By Natalie Si Yeung Yu King George V School, Year 12

Genetic diseases, caused by abnormal it ies in a person’s genome, are typically extremely difficult to treat, and many are incurable. Spinocerebellar ataxia (SCA) is one of them. It is a degenerative disease that eventually strips patients of their ability to coordinate movement. There are numerous types of SCA, with each type affecting a different gene and manifesting into a specific set of symptoms. Physiotherapy is often prescribed but only relieves symptoms to a certain degree. SCA40 was discovered by Prof. Edwin Ho-yin Chan during a three-year study of the genetic sequence of SCA patients in Hong Kong. He is Professor of Life Sciences at The Chinese University of Hong Kong and Director of the Laboratory of Drosophila Research.

In the latter part of the 90s, it was nigh impossible to identify genes that caused genetic diseases. The gene mutation responsible for causing cystic fibrosis, for instance, was not discovered until 1988 by Francis Collins, Lap-Chee Tsui and John R. Riordan. As a high school student and college freshman, Prof. Chan aspired to follow in their footsteps. In his junior year in college, Prof. Chan met his mentor, Dr. Sandy Luk, who urged him to first understand the biology of normal individuals before investigating pathological conditions. Equipped with his mentor’s sage advice, he began studying developmental biology on the fruit fly, Drosophila melanogaster and conducting research which helped explain how genes control an organism’s egg development, as many genetic d i seases unfo ld f rom young. Thus began h i s commitment to biomedical research.

Prof. Chan’s l i fe’s work began in 2002 after he had returned to Hong Kong from University of Pennsylvania, br inging with him the dream to dedicate himself to the SCA patient society. Together with the Hong Kong Spinocerebellar Ataxia Association, scientists, neurologists and genetic counsellors, they created a spinocerebellar ataxia patient registry that compiled patient data. It was during this period that they came across the SCA40 family – where five individuals were diagnosed with adult-onset spinocerebellar ataxia. Using genetic and biochemical analyses, Prof. Chan and his team were able to isolate the mutation in a gene called CCDC88C in these patients. Carriers of this gene mutation will develop SCA40.

Ident i f icat ion of the mutat ion i s p ivotal to developing better treatment and a potential cure to SCA40. “We take a structure-based drug design approach to develop inhibitors that can neutralise RNA-tox icity in SCAs. Based on the tox ic RNA structure, we virtually fit molecules to the RNA and attempt to find one that binds tightly to the toxic RNA,” said Prof. Chan, “After we identify such molecule(s), we then synthesise these compounds in the lab and then test them in our disease models, including iPSC, Drosophila and mice”.

Parallel to the research on SCA40, Prof. Chan and his team also investigate other neuromuscular diseases, including myotonic dystrophy and amyotrophic lateral sclerosis (ALS). The latter garnered viral attention in 2014 in an activity called “the ALS Ice Bucket Challenge”, aiming to bring awareness and donation toward ALS research.

23

The Discovery of SCA40 with Prof. Ho-yin ChanSCA40–

By Teresa Ming Shan Fan

Prof. Chan insists that creativity, paying attention to unobvious phenomena

and perseverance are the keys to being a successful scientist.

He also suggested, “Work hard, play harder!”

Many myths shroud the rhinovirus, the culprit responsible for causing the common cold, including the set of circumstances in which the virus transforms from being dormant to causing infections in humans. We know surprisingly little about this common virus and attempting to set right the old wives’ tale on staying away from cold weather to avoid getting sick, is more complex than it seems. Yale University’s Dr. Ellen Foxman and her research team investigate this very problem, exploring the mechanisms in which the rhinovirus manifests itself into symptoms and the body’s defense in response to infection.

Dr. Foxman’s research career began as an undergraduate, where she received a wide spectrum of research experiences. “During my first summer in college I did field research on Cliff Swallows, birds that migrate from the Midwestern United States to South America and back every year. The next summer, I was a research assistant in a virology lab, and the next year I worked in a yeast genetics lab”, she said. These experiences paved the path for her future career in medical research.

By the time she was in her medical residency, the normalisation of the use of polymerase chain reaction (PCR) to detect viruses helped to show that viral infections occur much more frequently

in patients than had been previously thought. “In fact, the data that emerged from use of these techniques revealed that certain viruses visited the body so often that they could be considered part of the microbiome”, said Dr. Foxman. However, as common as viruses were present, only half of the infections cause diseases and symptoms. “I became very interested in how variations in host-virus interactions affect the outcome of common viral infections”. This intr igue fuels her current research on the topic.

Several factors enhance the repl ication of the rhinovirus; one of which is temperature, and whether the rhinovirus replicates more readily in cooler environments. Previous observations have suggested that many strains of the virus do become more virulent at temperatures of 33 – 35 °C in the nasal cavity, as opposed to an average body temperature of 37 °C. Dr. Foxman and her group discovered with compelling evidence that at a lower temperature, the defense response of infected cells are compromised, thus allowing the virus to become more infectious. Other factors that lower the defense response of cells include patients who have asthma, but the mechanism is not yet understood.

Hong Kong’s flu seasons are marked with seas of mask-donning citizens in an effort to curb the spread of viruses. While masks act as barriers for airborne germs and viruses, Dr. Foxman believes there may be a possibility that warming up the nasal airway by wearing masks could also be a factor in extra protection against infection.

“The best strategy to prevent symptoms is probably

to prevent replication from happening in the first place, which is what

our airway epithelial cell defence mechanisms aim to do”.

Meanwhi le, D r. Foxman and her team wil l continue to s tudy and uncover the mechan i sms that change the way our airway defence systems deal with viruses. A deepe r unde r s tand i ng of these mechanisms is essential to the development of better strategies for the prevention of ubiquitous infections such as the common cold.

Photo credits: Yale Medicine

Micrograph of human bronchial epithelial cells, seven hours after exposure to rhinovirus 1B. Rhinovirus infection of airway epithelial cells results in accumulation of double stranded RNA (dsRNA; blue) during viral genome replication. Cells are also stained with Mitotracker red to reveal the location of mitochondria, the cellular structures associated with innate immune signaling via the RIG-I like receptor pathway(red).

Photo credits: Ulysses Isidro, Yale University senior thesis student.

25

By Teresa Ming Shan Fan

Acknowledgements Financial Support

The HK Electronic Industries Association Ltd. The HK Electronic Industries Association Education Foundation Ltd.

Print AdvisingHKUST Publishing Technology Centre

Special Thanks toMiss Catherine Wong

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